1. Field of the Invention
This disclosure relates generally to personal cleansing bars with lathering detergents and/or soaps. The bars have a high liquid content in combination with lathering additives and particulate silica to give the bars a desirable consistency.
2. Description of the Related Art
Personal cleansing with mild surface-active cleansing bar preparations has become a focus of great interest. The processability and smear properties of such bars have become a focus of even greater interest.
The fabrication of relatively pure xe2x80x9csoapxe2x80x9d bars is a well-worked-out engineering procedure involving milling, plodding and molding. Coco/tallow soap becomes quite plastic when warmed and can be easily plodded and molded under relatively low pressures. However, bars made with certain mild surfactants are very difficult to fabricate. The problems of formulating such bars are not limited to the performance characteristics of the finished bars. Thus, problems associated with mild synthetic detergent bars include bar processability, firmness, smear and mildness.
For example, most synthetic detergents and detergent-filler combinations do not become plastic and the machinery for fabrication must be specially designed. See e.g., U.S. Pat. No. 2,678,921.
Ideal processing should be fast and problem free in terms of milling, plodding and molding toilet bar formation. Most mild bar processings fall short in this respect.
Major drawbacks of most synthetic surfactant toilet bar formulations are harshness, poor lather, poor smear, and poor processability due to stickiness. It will be appreciated that processability, firmness, smear, mildness, lather, and rinsability make surfactant selection for mild personal cleansing bars a delicate balancing act. Thus, rather stringent requirements for formulating mild personal cleansing bars limit the choice of surfactants, and final formulations represent some degree of compromise. Mildness is often obtained at the expense of processability, effective cleansing, lathering, or rinsing, or vice versa. Processability is often obtained at the expense of smear.
A superior processable mild personal cleansing bar formulation with good mildness, good smear, good lather potential and good rinsability is difficult to formulate, but would be highly desirable.
It has now been discovered that particulate silica in certain ratios with emollients like oils, waxes, petrolatum, esters and/or humectants like polyols, e.g., glycerine, propylene glycol, polyethylene glycol, sorbitol, etc. in combination with detergent and/or soap additives can be formulated into cleansing bars of good hardness and acceptable processing characteristics. A unique feature of such compositions is that the high levels of the oil or liquid humectant phase provide functional benefits to skin by providing good foam without defatting the skin and also allowing the deposit of a residue with active ingredients. Silica give the bar the necessary properties for commercial fabrication.
A novel finding of these compositions is the effect of particulate silica having a high surface area on detergents from the groups consisting of sodium acyl isethionate, sodium alpha olefin sulfonates, disodium alkyl sulfosuccinate, soap base, tallow and coco sodium salts, and mixtures thereof, which produces a hard processable cleansing bar. Silica in the presence of these detergents, soaps and blends thereof, hardens the bars significantly. The hardening effect desirable for processing is observed at silica contents of a minimum of 1 part silica to 10 parts of liquid on a w/w basis, varying according to the particular liquids and waxes employed.
Particularly useful embodiments of the present cleansing bar compositions contain: a liquid phase consisting of either mineral, vegetable oils or polyols with or without the addition of waxes; amorphous silica; and soap, detergent or a mixture thereof. The composition is capable of foaming when combined with water during use. The present compositions provide formulations of a flowable phase of liquids, or of oils or of oils and waxes and silica which, upon combination with soap and/or detergents can be processed and stamped into a cleansing bar.